Sarnia police are joining in the warning about the dangers of fentanyl following a suspected fatal drug overdose.

Police issued the warning Wednesday night and say they believe two other people overdosed as well on fentanyl and they remain in hospital.

Police say the drug that was purchased was thought to be cocaine but it is now believed to have been laced with fentanyl, which they call a dangerous synthetic opioid. 

They ask individuals who may have recently purchased any street drugs not to use them.

In the case of a medical emergency involving drugs, police urge drug users to tell emergency dispatchers what they have used so that the proper treatment can be given.

Under the Good Samaritan Drug Overdose Act put in place on May 4, there is immunity from charges of simple possession of a controlled substance and charges regarding the violation of pre-trial release, probation order, conditional sentence, or parole associated with possession of a controlled substance for individuals who seek emergency medical treatment or law enforcement assistance for themselves or another person.

Last week, London police and health officials also issued a warning that some street drugs were believed to be laced with fentanyl.